Oil-soluble bis(methylphosphonodisulfides



United States Patent 3,309,428 OIL-SOLUBLE BISMETHYLPHOSPHONO-DISULFIDES George M. Calhoun, Cleveland, Ohio, and Hyman Diamond,Sacramento, Califi, assignors to Shell Oil Company, New York, N.Y., acorporation of Delaware No Drawing. Original application Dec. 23, 1960,Ser. No. 77,817, now Patent No. 3,238,131, dated Mar. 1, 1966. Dividedand this application July 16, 1965, Ser.

5 Claims. (Cl. 260-932) This patent application is a division ofcopending patent application Ser. No. 77,817 filed Dec. 23, 1960, nowPatent No. 3,238,131.

This invention relates to a new'and novel class of oilsoluble acidicbis(phosphonomethyl)disulfides for use in fuels and lubricants. Thecompounds of the present invention can be represented by the generalformulas:

where R is hydrogen and A is a C alkyl radical or a C alkylamine, e.g.,octylamine, laurylamine, stearylamine, etc., or branched-chain primaryaliphatic amines, e.g., t-C alkylamine, such as t-C3H1'1NH2, C H NH tot-C15H31NH2, 01' t-C1gH37NH2 to I'C22H45LNH2, 01' C secondary aliphaticamines, such as diamylamine, di-Z-ethylhexylarnine, didecylamine, etc.

The acidic bis(phosphonomethyl)disulfides are prepared by reacting analkali disulfide, e.g., sodium or potassium disulfide, with a halomethylphosphono compound such as monohydrocarbyl ester ofchloromethylphosphonic acid in a suitable solvent such as an aqueousalcoholic solution, at reflux temperature and under inert conditionsuntil the reaction is completed which normally requires from 1 to about5 days. Suitable halomethylphosphonic compounds include monoalkylchloromethylphosphonates, e.g., monobutyl chloromethylphosphonate,mono-2-ethylhexylchloromethylphosphonate, monolaurylchloromethylphosphonate, monobenzyl chloromethylphosphonate, and thelike.

A preferred method of making the disulfides of this invention is toreact sodium or potassium disulfide With a partial ester ofchloromethylphosphonic acid in an alcoholic solution under refluxconditions and under an inert atmosphere for about 24 hours andthereafter neutralizing to a pH of about 7 and ether extract and waterwashing the acidic bis(phosphonomethyl)disulfide. The product can beused as such or treated with a strong acid such as hydrochloric acid tospring the free acid which can be converted into desired partial estersor amine salts for use as oil, fuel and grease additives as Well asother uses.

The following examples illustrate the preparation of additives for usein accordance with the present invention.

EXAMPLE I Stoichiometric amounts of sodium disulfide and monobutylmonochloromethylphosphonate were refluxed for about 24 hours in analcoholic solution (ethanol) under nitrogen atmosphere and thereafterthe pH of the mixture was adjusted to around 7 and the bis(monobutylphosphonomethyl)disulfide was ether extracted and water 3,309,428Patented Mar. 14, 1967 "ice washed to give a 6065% yield ofbis(monobutyl phos- EXAMPLE II Di-2-ethylhexylamine salt of his(monobutylphosphonomethyl)disulfide was prepared by reacting the productof Example I with di-Z-ethylhexylamine in an amount sufficient toneutralize completely both acid (OH) groups, at about 50 C. in analcoholic solution and thereafter recovering the amine salt from thealcoholic solution.

EXAMPLE III salt of bis(monobutyl phosphonomethyl)disulfide.

Additional improvement of oil and fuel compositions containing theadditives of the present invention is accomplished by addition of smallamounts of alkylated bisphenols. Y

The alkylated bisphenols may contain from 1 to 8 alkyl groups, butpreferably they contain from 2 to 6 alkyl groups; alkylated bisphenolshaving 4 alkyl groups are particularly preferred. Each of the alkylgroups may contain from 1 to 10 carbon atoms, preferably 2 to 6 carbonatoms, and especially 4 carbon atoms. Furthermore, the alkyl groups inany particular bisphenol may be the sameor different and may also beprimary, secondary or tertiary alkyl groups. Bisphenols containing atleast one tertiary alkyl group are particularly preferred.

As examples of the alkylated bisphenols which may be used according tothe invention, there are mentioned bis 3-ethyl-4-hydroxyphenyldisulfide,

bis 3-methyl-4-propyl-S-hydroxyphenyl disulfide,

bis 2-isopropyl-3-butyl-5-hydroxyphenyl) selenide,

2,2'-diethyl-3-tertiary-butyl-4,4'-dihydroxydiphenyl selenide,

bis 1,2 (2,6-ditertiary-butyl-4-hydroxyphenyl thiaethane.

bis 1,2 2,5 -diisopropyl-3-hydroxyphenyl thiaethane,

bis 3 ,5 -ditertiary-butyl-4-hydroxyphenyl) sulfide,

2,4-diisobutyl-3-hydroxybenzyl-2',4-dipropyl-3 hydroxy-benzyl sulfide,

bis 1,2 3-octyl-5-tertiary'butyl-4-hydroxyphenyl) ethane,

bis 1,1 2,6-diisopropyl-4-hydroxyphenyl) ethane,

1,2-bis 2,4-ditertiary pentyl-3-hydroxyphenyl) propane,

bis 2,2 (4,5 -ditertiary-butyl-2-hydroxyphenyl) propane,

bis Z-tertiary-butyl-5-isopentyl-4-hydroxyphenyl) amine,

bis (3 ,S-dibutyl-S-hydroxyphenyl ether,

bis 2,6-dipropyl-4-hydroxyphenyl ether.

Preferred compounds are the alkylated bisphenols having a sulfur ormethylene bridge, the former includingbis(2,5-dipentyl-4-hydroxyphenyl)sulfide, bis 2,5 -dihexyl-3-hydroxyphenyl sulfide, bis (2-methyl-5-tertiary-butyl-4-hydroxyphenylsulfide, bis(Z-methyl-S-tertiary-butyl-6-hydroxyphenyl)sulfide and,particularly, bis 3-tertiary-butyl-5-methyl-2-hydroxyphenyl)sulfide,

and examples of the latter, namely, alkylated bisphenols having amethylene bridge, include bis (2,3 -ditertiary-butyl-4-hydroxyphenylmethane,

bis (2,5 -ditertiary-butyl-4-hydroxyphenyl methane,

bis 2,6-ditertiary-butyl-4-hydroxyphenyl methane,

bis 3 ,5 -ditertiary octyl-4-hydroxyphenyl) methane,

bis(3 -tertiary-butyl--tertiary-octyl-4-hydroxyphenyl) methane, andespecially,

bis (3 ,5 -ditertiary-butyl-4-hydroxyp'henyl) methane.

Also, the phosphonomethyl disulfide additive, alone or in combinationwith a bisphenol, appears to co-act with certain phosphorus compounds togive additional unexpected improvement in anti-wear and anti-scuffing.Thus, this desirable improvement can be imparted to lubricants of thisinvention by also incorporating a small amount (0.0'12% preferably0.14%) of a partial or full ester of an organic phosphorus compound.Phosphorus compounds of this type include alkyl, cycloalkyl, alkaryl,aralkyl, and aryl phosphites, phosphates, phosphonates, and their thioderivatives, such as C alkyl phosphites, e.g., diand tri-butyl, octyl,lauryl, stearyl, cyclohexyl, benzyl, cresyl, phenyl phosphite orphosphates, as well as their thio derivatives; P S -pine oil reactionproduct, and metal salts thereof such as Na, K, Ca or Ba salts of P Sterpene reaction product; dibutyl methylphosphonate, dibutyltrichloromethylphosphonate, dibutyl monochloromethylphosphonate, dibutylchlorophenylphosphonate, and the like. The esters of pentavalentphosphorus acids such as diphenyl, dicresyl, triphenyl, tricresyl,trilauryl and tristearyl orthophosphates, P S -terpene reaction productsand mixtures thereof are preferred.

Minor amounts of each class of additives are sufficient for a highlyeffective combination. The bis(phosphonomethy1)disul' fide may be usedin an amount of about 0.1- preferably about 0.2-5% by weight, whileabout 0.052%, preferably about 0.1 1% of the methylene bisphenol orsulfide derivative thereof is highly useful and about 0.1%-2% of anorganic phosphorus compound as described in the preceding paragraph.

The additives of the present invention may be used to improve varioushydrocarbon lubricating oils, whether of natural origin or synthetic,especially oils which are substantially paraffinic and/ or naphthenic;these may contain substantial proportions of hydrocarbons havingaromatic character, but the amounts and types of components should besuch that the Dean and Davis (Chem. and Met. Eng., vol. 36, 1929, pp.618-619) viscosity index of the base oil is at least 80, preferably 90to 150.

The oil may be derived from a highly paraffinic crude, in which casedistillation and/ or dewaxing may be sufficient to provide a suitablebase stock; a minimum of chemical or selective solvent treatment may beused if desired. Mixed-base crudes and even highly aromatic crudes whichcontain paraffinic hydrocarbons also provide suitable base stocks bywell known refining techniques. Usually, these comprise the separationof distillate fractions of suitable boiling range followed by selectivesolvent extraction with solvents such as furfural, phenol, and the liketo provide raffinate fractions which are suitable for further refiningby dewaxing or chemical treatment such as sulfuric acid treatment, etc.Thus, it may be a refined hydrocarbon oil obtained from a paraffinic,naphthenic, asphaltic or mixed-base crude, and/ or mixtures thereof,such as SAE 5W, 10W, 20W, 20, 30, 40, 50 mineral oils. The hydrocarbonoils may be blends of different mineral oil distillates and brightstock; they may have blended therewith, in minor but compatibleproportions, fixed oils, such as castor oil, lard oil and the like and/or with synthetic lubricants, such as polymerized olefins, e.g.,polyisobutylene.

The following compositions are representative of the invention:

Composition A Percent EXample I additive 2 1010 Mineral oil W BalanceComposition B Example 11 additive 2 1010 Mineral oil Balance CompositionC Example III additive 2 1010 Mineral oil Balance Composition D ExampleI additive 2 Bis(3,5-ditert-butyl-4-hydroxyphenyl)methane 0.75

1010 Mineral oil Balance Composition E Example II additive 1 SAE 30Mineral oil Balance Composition F Example I additive 2 SAE Mineral oilBalance Composition G Example I additive 2 Bis 3 ,5-ditert-butyl-4-hydroxyphenyl methane 0.5

SAE 90 Mineral oil Balance Composition H Example I additive 5 Ucon50H=B660 (polyethylene-propylene glycol having a SUS viscosity at F. of660') Balance Composition I Example I additive 2 Di-Z-ethylhexylsebacate Bal ance Composition J Example I additive 1 Leaded gasoline (3cc. of TEL) Balance Composition K Example I additive 0.1 Fuel oil (No.2) Balance Speed, 3200 rpm.

Oil temperature, 100 C.

Oil flow-rate, 10 cc./sec.

Load in increments; 5 min. at each setting Results of the evaluationsare given in Table I and, for the purpose of comparison, the resultsobtained from the use of the base oil alone and with other known extremepressure compositions are also given.

Table I Composition: Score load, lbs/in. A through I 6,400 1010 mineraloil +2% C alkenyl succinic acid 1,400 1010 mineral oil +2% malonic acid2,800 1010 mineral oil +2% 3-hexadecyl adipic acid -i 1,400

Table IContinued Composition: Score load, lbs/in.

1010 mineral oil +2% dodecylmercaptosuccinic acid 1,400

1010 mineral oil +10% glycerol monooleate 1,800 1010 mineral oil +2% C HOH (OXO process) 600 Other representative compositions of this inventionwhich are similarly effective are:

Compositions of this invention are particularly applicable forhigh-temperature, high-speed use as in aviation engines, automotiveengines and truck engines, as well as industrial equipment operatingunder the conditions described in this invention.

We claim as our invention;

1. An oil-soluble bis(mono-C alkyl phosphonomethyl)disulfide.

2. An oil-soluble bis(monobutyl phosphonomethyl)disulfide.

3. An oil-soluble amine salt of bis(mono-C alkylphosphonomethyDdisulfide.

4. An oil-soluble amine salt of bis(-monobutyl phosphonornethyl)disulfide.

5. An oil-soluble t-octadecylamine salt of bis(rnonobutylphosphonomethyl) disulfide.

References Cited by the Examiner UNITED STATES PATENTS 2,857,304 10/1958Birum 16722 CHARLES B. PARKER, Primary Examiner.

B. BILLIAN, Assistant Examiner.

1. AN OIL-SOLUBLE BIS (MONO-C1-8 ALKYL PHOSPHONOMETHYL) DISULFIDE.